Instrument for measuring pressure

Abstract

An instrument for measuring the pressure exerted upon a portion of the body of a bedridden individual lying on a mattress by that section of the mattress which is engaged by this body portion. A small flexible hollow member has a first air inlet and is adapted to be positioned for use between the body portion and the mattress section. A switch is disposed in the member with connecting leads extending out of the member. The switch is open when the air pressure in the member is at least equal to the exerted pressure and is closed when the air pressure in the member is less than the exerted pressure. A circuit including a lamp and an electric power source is connected to the switch to cause the lamp to be energized and lit when the switch is closed, the lamp being deenergized and dark when the switch is open. An air pressure meter has a second air inlet. A manually operated air pump is connected to both air inlets. When the member is positioned for use with the switch closed and the lamp energized, the pump is actuated and the pressure in the member is increased until the lamp is deenergized. The meter at the instant the lamp is deenergized displays the exerted pressure.

What is claimed is: 
     
       1. An instrument for measuring the pressure exerted upon a portion of the body of a bed ridden individual lying on a mattress by that section of the mattress which is engaged by this body portion, said instrument comprising: a small flexible hollow member having a first air inlet and adapted to be positioned for use between the body portion and the mattress section;   a normally closed switch disposed in the member with connecting leads extending out of the member, the switch being opened when the air pressure in the member is at least equal to the pressure exerted upon the body portion by the mattress section and being closed when air pressure in the member is less than the exerted pressure;   a circuit including a lamp and an electric power source, the circuit being connected to the switch to cause the lamp to be energized and lit when the switch is closed, the lamp being deenergized and dark when the switch is open;   an air pressure meter having a meter face and a second air inlet and calibrated to display on the face air pressure readings measured in pressures above atmospheric pressure; and   a manually operated air pump connected to the first and second air inlets whereby when the member is positioned for use with the switch closed and the pump is actuated, the air pressure in the member is increased until the lamp is deenergized, and the meter at the instant the lamp is deenergized displays the exerted pressure.   
     
     
       2. The instrument of claim 1 wherein the switch includes first and second horizontal flexible blade type conductors, one conductor overlying the other, the conductors being engaged when the switch is closed and being disengaged when the switch is open. 
     
     
       3. The instrument of claim 2 wherein the member is flat and flexible and has first and second closely spaced opposite walls, each conductor being secured to the inner surface of the corresponding wall, said walls being separated to an extent at which the conductors are disengaged only when the air pressure in the member is at least equal to the exerted pressure. 
     
     
       4. The instrument of claim 3 further including a housing for the circuit, meter and pump, the pump having a squeeze type diaphram, the circuit including at least one electric cell, the meter having an exposed face, the lamp being disposed adjacent the meter face so that the lamp and meter face are simultaneously observable. 
     
     
       5. The instrument of claim 4 wherein the housing has a handle and the pump and cell are disposed in the handle.